Processes for forming an aldehyde by the hydroformylation of an olefinically unsaturated organic compound in the presence of a rhodium-phosphorus complex catalyst and free phosphorus ligand are well known in the art, as seen, e.g., by U.S. Pat. Nos. 3,527,809; 4,148,830; and 4,247,486. The most commonly recommended phosphorus ligands are monophosphines and monophosphite compounds, especially triphenylphosphine.
In addition assignee's U.S. patent application Ser. No. 293,190, now U.S. Pat. No. 4,400,548, is directed to an improved hydroformylation process wherein organic tertiary bisphosphine monooxide ligands are employed in place of such conventional phosphorus ligands. While the use of such bisphosphine monooxide ligands furnish the process with a rhodium complex catalyst having improved high temperature stability and do improve the processing selectivity of desired linear aldehyde product in terms of amount of linear aldehyde product per given amount of olefinic starting material, such bisphosphine monooxide ligands also have the drawback of substantially reducing the reaction rate (gram moles of aldehyde product produced per liter per hour) of such hydroformylation processes in relation to that obtained when employing e.g. triphenylphosphine ligand. This disadvantage is further magnified with regard to large scale commercial type operations wherein a primary consideration in hydroformylation is the ability of the process to produce the maximum amount of aldehyde product within a given period of time rather than per given amount of olefinic starting material.
Thus practical considerations for a commercial hydroformylation process in producing normal or straight chain aldehyde product involve a balancing of such processing factors as e.g. the reaction rate, catalyst stability and the proportion of normal to branched isomeric aldehyde products formed, and the balanced optimization of such processing factors is of major importance to the state of the art.